^^94 LOCAL TLSSLE REACTIVITY 



ol a l)a( tci ial (cll. Ilic work with diplitlu'i ia wlicre the ra\()ial)le 

 efiect ol antitoxin is ( Icarly established, shows that strains (oni- 

 j)arati\ely a\iiiilent may he highly to\i<>enie and vi(e versa. Lhis 

 is ^vell l)orne out l)y tlic e\|x'rinients of Anderson, Happold, 

 McCleod and Thomson on \arioiis tyjies ol B. (lij)lillirriae aheady 

 quoted (p. ^^06) . 



Pr()te( tion tests dej^end on the antibodies capal)le ol sa\ing an 

 animal Irom the lethal effect of live virulent cultures. The viru- 

 lence of a "iven microoroanism is titrated. The titrated live bac- 

 teria are mixed with the imminie serum, and if the animal 

 siuvives the injection of the mixture, the serum is considered 

 protective. In these tests one is dealing with an overAvhelming 

 septicemia ^vhereloy the unprotected animal dies within twenty- 

 four to seventy-t\vo hotus following the injection. The infection is 

 induced by the intraj^eritoneal introduction of a large amount of 

 li\e organisms. In spontaneous infections the process is apparently 

 altogether different, since the inocidation goes through different 

 routes and the infection takes place after a definite incubation 

 period. The manner of production of spontaneous infection im- 

 questionably results in processes of partial immiuiity and sensi- 

 tization ^vhich are apparently totally absent in overwhelming 

 septicemias of mice employed for protection experiments. Further- 

 more, the mechanism of the passive protection conferred by 

 the administration of immune serum differs significantly from a 

 toxin-j-antitoxin reaction. As pointed out before, any amoiuit of 

 toxin can be neutralized pro\'ided a sufficient amount of anti- 

 toxin is supplied. In protection experiments on mice no increase 

 in the amount of serum administered saves the life of a mouse 

 if the dose of pneumococcus exceeds a certain size. Moreover, a 

 large dose of serum is necessary to prevent miUtiplication of 

 pnetnnococci. A slightly smaller dose of serum may be just as in- 

 effective as no serum at all. 



Until recently, the studies on the protective antibodies were 

 limited almost exclusively to the anti-pneumococcus serum since 

 the pneumococci ^vere the only microorganisms in ^vhich a fairly 

 stable viriUence could be obtained. The recent in\'estigations of 

 Nungester, Wolf and Jourdonais (1932) , Miller (1933, 1935) > 

 Rake (1935) , and P(nvell and Jamieson (1936) deserve special 

 consideration. They foiuid that the injection of a mixture of com- 

 mercially prepared mucin ^vith bacteria {B. typJiosus, meningo- 

 coccus, etc.) into the peritoneum of a mouse, preferably a Swiss 



